Mysterious bio-duck sound attributed to the Antarctic minke whale (Balaenoptera bonaerensis)

For decades, the bio-duck sound has been recorded in the Southern Ocean, but the animal producing it has remained a mystery. Heard mainly during austral winter in the Southern Ocean, this ubiquitous sound has been recorded in Antarctic waters and contemporaneously off the Australian west coast. Here, we present conclusive evidence that the bio-duck sound is produced by Antarctic minke whales (Balaenoptera bonaerensis). We analysed data from multi-sensor acoustic recording tags that included intense bio-duck sounds as well as singular downsweeps that have previously been attributed to this species. This finding allows the interpretation of a wealth of long-term acoustic recordings for this previously acoustically concealed species, which will improve our understanding of the distribution, abundance and behaviour of Antarctic minke whales. This is critical information for a species that inhabits a difficult to access sea-ice environment that is changing rapidly in some regions and has been the subject of contentious lethal sampling efforts and ongoing international legal action.     

Cardiopathic effects of dichloroacetate in the fetal Long-Evans rat.

Dichloroacetic acid (DCA) is a by-product of the chlorine disinfection of water and may occur in treated water at levels exceeding 100 micrograms/L. Previous studies revealed teratogenic effects, particularly heart malformations, at high doses (900-2,400 mg/kg given on days 6-15 of pregnancy). In a series of three studies, groups of 7-10 Long-Evans rats were dosed with 1,900 mg/kg of DCA on days 6-8, 9-11, or 12-15; with 2,400 mg/kg on days 10, 11, 12, or 13; and with 3,500 mg/kg on days 9, 10, 11, 12, or 13, in an attempt to determine the most sensitive period and further characterize the heart defect. In a fourth study, six dams were treated with 1,900 mg/kg of DCA days 6-15 of pregnancy, and 56 fetuses were harvested for light microscopy of the heart. Eight control fetuses from four litters were also examined. No heart malformations were seen in the groups treated with 1,900 mg/kg DCA days 6-8 but were present in the group treated on days 9-11 and 12-15, with the higher incidence occurring on days 12-15. Single doses of 2,400 mg/kg DCA given on days 10, 11, 12, or 13 resulted in a much lower incidence of cardiac malformations, which occurred only on days 10 and 12. The high dose of DCA (3,500 mg/kg) did not increase the incidence of heart defects but showed that dosing on day 9 as well as on days 10 and 12 would produce the defect. The defects seen were characterized as high interventricular septal defects (H-IVSD). Light microscopy showed that the defect was caudal to the semilunar valves, with the anterior right wall of the aorta communicating with the right ventricle. Another aspect of the defect is at the level of the semilunar valves, with the right cusp or sinus of Valsalva in communication with the right ventricle. The defects are discussed more fully and methods for further study suggested.     

Control in congenital adrenal hyperplasia monitored by frequent saliva 17OH-progesterone measurements

Treatment in a group of 19 patients with congenital adrenal hyperplasia (CAH) has been monitored by frequent, serial measurements of saliva 17OH-progesterone (17OHP) concentrations. Detailed 17OHP profiles were obtained during consecutive weekend days and every 1-2 h over a separate 24-hour period. Patients showed a marked diurnal rhythm in 17OHP levels, particularly when treated with hydrocortisone. In some patients, 10 mg/m2/day of hydrocortisone was sufficient glucocorticoid replacement to produce adequate control, although there was considerable individual variation. Saliva 17OHP profiles provided valuable information on the efficacy of hydrocortisone, cortisone acetate, prednisolone and dexamethasone as glucocorticoid suppressive regimes in the treatment of CAH. Preliminary results suggest that hydrocortisone given in two divided doses during the day, supplemented by a small dose of prednisolone at bedtime, is suitable treatment for CAH patients who are still growing. In the patient who has completed statural growth, single daily dose dexamethasone therapy ensures adequate adrenal suppression and is convenient in the longterm.     

Stabilization of DNA triple helices by a series of mono- and disubstituted amidoanthraquinones.

We have used quantitative DNase I footprinting to measure the relative affinities of four disubstituted and two monosubstituted amidoanthraquinone compounds for intermolecular DNA triplexes, and have examined how the position of the attached base-functionalized substituents affects their ability to stabilize DNA triplexes. All four isomeric disubstituted derivatives examined stabilize DNA triplexes at micromolar or lower concentrations. Of the compounds studied the 2,7-disubstituted amidoanthraquinone displayed the greatest triplex affinity. The order of triplex affinity for the other disubstituted ligands decreases in the order 2,7 > 1,8 = 1,5 > 2,6, with the equivalent monosubstituted compounds being at least an order of magnitude less efficient. The 1,5-disubstituted derivative also shows some interaction with duplex DNA. These results have been confirmed by molecular modelling studies, which provide a rational basis for the structure-activity relationships. These suggest that, although all of the compounds bind through an intercalative mode, the 2,6, 2,7 and 1,5 disubstituted isomers bind with their two side groups occupying adjacent triplex grooves, in contrast with the 1,8 isomer which is positioned with both side groups in the same triplex groove.     

Palm Chromosome Studies Facilitated by Pollen Culture on a Colchicine-Lactose Medium

This technique is very useful where pollen is readily available and when roots or microspore mother cells are difficult to obtain or to process. It provides a relatively uniform means of studying chromosomes in a great number of species. Pollen is collected from buds at anthesis or the day before and sown on a medium containing H₃BO₃, 100 ppm; colchicine, 0.04%; lactose, 12%; gelatin, 5%; egg albumen, 1 drop in 10 ml. The gametic chromosome complement is studied at mitosis of the generative cell in the pollen tube. In species which have sufficiently large chromosomes it is possible to construct idiograms for comparative studies. All palm species here reported have a haploid complement of n = 18, and the chromosomes range in length from 0.5-3.5 μ.     

A mutant of herpes simplex virus type 1 exhibits increased stability of immediate-early (alpha) mRNAs.

vhs1 is a herpes simplex virus type 1 mutant defective in the shutoff of both host and alpha polypeptide synthesis. In cycloheximide reversal experiments, alpha mRNAs were significantly more stable in vhs1-infected cells than in cells infected with wild-type virus, whether assayed by in vitro translation or Northern blotting.